Semiconductor quantum dots (QDs) are nanometer-sized particles with unique optical and electronic properties, and are currently under intensive research for a broad range of applications such as solar energy conversion and molecular and cellular imaging. Significant advances have been made in the chemical synthesis of highly crystalline and monodispersed QDs, especially with the use of organometallic and chelated cadmium precursors, noncoordinating solvents, and inorganic passivating shells. However, the resulting nanocrystals are often hydrophobic and must be encapsulated and solubilized post synthesis for many important applications. Aqueous synthetic procedures have been used as alternative approaches to prepare water soluble QDs, using small thiol-containing molecules or polymers with carboxylic acid functional groups as stabilizing agents. But these methods do not yield QDs with the fluorescence brightness or size monodispersity that are often achieved with the high-temperature organic procedures.